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Author
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Topic: Electronic ignition hookup check (MSD)
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65ponycar
Gearhead Posts: 873
From: Dayton, OH
Registered: Jul 2003
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posted 11-23-2004 07:44 PM
 
Never ending questioning with me--So I'm running a MSD ready-to-run distributor. It is new. Have a question about the install; since I started this engine project buildup from scratch (six cylinder conversion) I have no reference from the original car, or since I went electronic on this. How much voltage is needed for the positive lead on an msd(or probably all others) electronic distributor? A full 12v? The wiring harness included has a connection for: (1)positive side of coil (2)negative side of coil (3) engine ground. Question is should I run a relay to get 12v to the positive side of coil, or is it inteneded to run off the pink wire (resistor from ignition switch). Right now I have it wired off of the directly as stated with only the lower voltage to the positive side of the coil. Just making sure that is right, and that I got the sucker wired properly!!! thanks - Dan
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SteveLaRiviere
Administrator Posts: 48752
From: Saco, Maine
Registered: May 99
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posted 11-23-2004 08:46 PM
Yes, you want a full 12v for electronic ignition for it to run as intended. You want a nice keyed power source.MSD is famous for their tech support, and they have a really decent web page with lots of sample wiring diagrams. ------------------
'70 Mustang Mach 1 351C 4V/FMX/3.25 Open
'70 Mustang Convertible 250 I6/3 speed/2.79 Open
'72 Mustang Sprint Hardtop 351C 4V/FMX/4.30 Trac Loc
'94 F-150 XL 5.8L/E4OD/3.55 Limited Slip
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65ponycar
Gearhead Posts: 873
From: Dayton, OH
Registered: Jul 2003
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posted 11-23-2004 09:40 PM
quote:
Originally posted by SteveLaRiviere:
Yes, you want a full 12v for electronic ignition for it to run as intended. You want a nice keyed power source.MSD is famous for their tech support, and they have a really decent web page with lots of sample wiring diagrams.
Thanks Steve - Here is a link to a pdf version of the install book I got. http://www.msdignition.com/pdf/pn_8350_8352_8354.pdf Page 7 the diagram indicates (to my little electrical knowledge) that the "key wire" is a 12v source; however I seem to recall some people saying this wire has a ballast or resistor on it. Tomorrow I will check what kind of volts my wire has with a multimeter. If the wire is not supplying the 12v where would be the best source (or nearest) to tap into? I suppose a simple rely would work, but anything that could cause harm, like why did for not intend for 12v to be at the coil? thanks!
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66 fastback
Gearhead Posts: 223
From: Califon, NJ 07830
Registered: Oct 2003
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posted 11-23-2004 10:01 PM
I put this exact dizzy in my stroker. I bypassed the resistance wire in the underdash harness so I could get 12 volts to the coil. I cut the harness about 2" from the firewall junction, and soldered in a 14 gauage wire that I connected to the ignition switch plug. I left the old resistance wire in place should I ever desire to return to the original system.
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65ponycar
Gearhead Posts: 873
From: Dayton, OH
Registered: Jul 2003
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posted 11-23-2004 10:34 PM
quote:
Originally posted by 66 fastback:
I put this exact dizzy in my stroker. I bypassed the resistance wire in the underdash harness so I could get 12 volts to the coil. I cut the harness about 2" from the firewall junction, and soldered in a 14 gauage wire that I connected to the ignition switch plug. I left the old resistance wire in place should I ever desire to return to the original system.
Beautiful  Exactly what I needed to know! I think I had better get on this, excited to have my first chance to work on the mustang since I left for school back in September! Right now I'm working on narrowing the list of possibilities that have turned my new/rebuilt 302 into a dog...
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65ponycar
Gearhead Posts: 873
From: Dayton, OH
Registered: Jul 2003
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posted 11-29-2004 08:09 PM
Thanks Steve and 66 Fastback!I checked it out, with the original "keyed" power wire to the ignition coil from the key I had 6.49V. I created a small "T" using original style push connectors and tapped into the full 12v source after the key but before the pink resistor wire. Should I ever want to go back (doubtful ) I can just pull the "T" out and plug the original harness back together. I left the old ignition coil wire in the wire harness loom (for safe keeping). Here is a diagram so this post can hopefully help someone in a search later on. http://www.hammar.dyndns.org/~djhamma/wiring/1965/1965c.jpg Having a full 12 volts my motor now revs smoothly/quickly!!! Man what a relief! I actually was able to take the car for a ride, it would barely idle before. Symptoms were exactly what is described as "having the distributor 180* out". Hope this helps someone in the future... Thanks again, Dan Note: Edit so only a link to picture (It is huge!) [This message has been edited by 65ponycar (edited 11-29-2004).]
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65ponycar
Gearhead Posts: 873
From: Dayton, OH
Registered: Jul 2003
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posted 12-01-2004 08:02 PM
I hope no one minds I defaced the jpeg a bit to show this...68coop and others this is what I did, correct me if there is a problem or you can't understand me.  [This message has been edited by 65ponycar (edited 12-01-2004).]
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